组织工程软骨种子细胞研究进展

组织工程是应用生命科学和工程学原理,研究开发能够修复、维持或改善组织损伤能力的生物替代物的一门学科[1]。利用组织工程方法再造软骨,为临床上软骨缺损的修复带来了新的途径,种子细胞作为软骨组织工程学研究的首要方面,它的来源途径也就尤为重要。目前的组织工程软骨种子细胞的来源主要为自体软骨细胞、同种异体软骨细胞、成纤     

组织工程软骨种子细胞研究进展

组织工程是应用生命科学和工程学原理,研究开发能够修复、维持或改善组织损伤能力的生物替代物的一门学科[1]。利用组织工程方法再造软骨,为临床上软骨缺损的修复带来了新的途径,种子细胞作为软骨组织工程学研究的首要方面,它的来源途径也就尤为重要。目前的组织工程软骨种子细胞的来源主要为自体软骨细胞、同种异体软骨细胞、成纤维细胞、干细胞、转基因细胞等,成熟软骨细胞是最常被关注     

组织工程骨软骨复合组织构建研究进展

本文综述了近几年骨软骨组织工程研究进展。查阅近几年有关骨软骨组织工程的文献,于支架材料、信号因子、种子细胞及制备技术等方面加以总结分析。骨软骨组织工程根据仿生学理论与方法完成组织替代物的制备并对损伤或有缺陷组织进行修复,可有效恢复受损骨软骨组织的结构功能与力学特性,是一种具有长远意义的综合交叉学科。目前,骨软骨组织工程策略针对骨软骨损伤取得了一定的成果,但仍需进一步发展,最终为骨软骨损伤提供一种成熟的临床治疗方法。     

不同浓度重组人BMP-7促进骨髓间充质干细胞复合组织工程支架材料TCP-COL体外构建组织工程软骨的研究

目的观察比较不同浓度重组人BMP-7对骨髓间充质干细胞复合组织工程支架材料TCP-COL体外构建组织工程软骨的影响。方法用梯度离心法获取人骨髓间充质干细胞（hMSCs）,将扩增的第3代hMSCs以1×10~7/ml的细胞浓度接种在支架材料TCP-COL上,分为三组进行培养：对照组（成软骨诱导液培养）,BMP-7（50）组（成软骨诱导液基础上加入50ng/ml的BMP-7）,BMP-7（100）组（成软骨诱导液基础上加入100ng/ml的BMP-7）。培养2周后进行扫描电镜观察（SEM）,苏木素伊红染色（HE）,阿尔新蓝染色,Ⅱ型胶原免疫组织化学染色（IHC）,荧光定量PCR（RT-PCR）,糖胺多糖定量（GAG quantification assay）研究。结果扫描电镜与苏木素伊红染色结果显示细胞在TCP-COL生物支架中分布均匀且紧密粘附在材料表面。阿尔新蓝染色,Ⅱ型胶原免疫组织化学染色,二型胶原（F=76.931,P〈0.05）,糖胺多糖（F=63.158,P〈0.05）荧光定量PCR,糖胺多糖定量（F=8.981,P〈0.05）结果显示BMP-7能有效促进人骨髓间充质干细胞复合支架材料TCP-COL体外成软骨,且100mg/ml的浓度应用效果大于50mg/ml。但在COL1基因的表达上,BMP-7（50）组和BMP-7（100）组都显著大于对照组（F=34.823,P〈0.05）。结论 BMP-7能有效促进人骨髓间充质干细胞复合支架材料TCP-COL体外成软骨,且100mg/ml的浓度应用效果大于50mg/ml,但应注意其促进骨质增生的作用。TCP-COL是一种有应用前景的生物支架材料。     

组织工程软骨种子细胞的研究进展

目的 综述组织工程软骨种子细胞及培养系统的发展近况。方法 广泛查阅近年来有关组织工程软骨种子细胞和培养系统的文献，进行综述。结果 回顾了组织工程软骨的种子细胞来源及培养方法，自体或异体软骨细胞仍然是目前软骨组织工程的主要细胞，三维立体细胞培养体系是现在主要的细胞培养体系。结论 组织工程软骨种子细胞的来源有待于进一步发掘，培养体系有待于进一步完善和发展。     

生长因子与组织工程软骨种子细胞的研究

组织工程是继细胞生物学和分子生物学之后 ,生命科学发展史上又一新的里程碑 ,标志着医学初步进入制造组织和器官的新时代。软骨则是第一种获得成功的组织工程化组织 ,也是当前组织工程研究的热点。由于利用组织工程技术修复软骨缺损 ,往往需要大量的细胞 (如耳缺损 ) ,而软骨细胞属于终末分化细胞 ,在体外扩增有限 ,且经过一段时间后 ,细胞开始老化 ,表型发生改变 ,转变为类成纤维细胞 ,由表达Ⅱ型胶原 ,转而表达Ⅰ、Ⅲ型胶原基质 ,丧失成软骨功能。因此如何防止细胞功能老化 ,寻求广泛的种子细胞来源 ,是软骨组织工程研究中首要解决的关键…     

软骨组织工程种子细胞的研究进展

利用软骨细胞与可降解生物材料,在体外构建透明软骨,进而移植修复关节软骨损伤,是软骨组织工程学研究的重要内容。体外构建透明软骨已取得成功,动物体内实验也取得阶段性成果。但仍存在不少问题,如软骨细胞在体外培养时的表型失分化及功能老化,以及难以在短期内获得足够量的软骨细胞。这些都直接制约着软骨组织工程的发展,限制了其临床应用。许多学者从不同方面就此进行了大量研究,取得了一定进展。     

组织工程骨软骨复合组织构建研究进展

采用组织工程学方法构建骨软骨复合组织是在以往单独构建骨、软骨基础上发展而来的新的研究领域。本文综述了组织工程骨软骨复合组织构建概况、支架材料、种子细胞的选择等方面的最新研究进展。     

软骨内成骨的调控

骨骼的纵向生长不仅需要激素的调节，同时也需要旁分泌的局部调节因子的调节，因而调节因子可分为系统性调节因子和局部调节因子。系统性调节因子包括生长激素、甲状腺素、雌激素、雄激素、维生素D3、视黄酸及皮质激素等。局部调节因子包括骨形态发生蛋白（BMPs）、成纤维细胞生长因子（FGFs）、Ihh／甲状旁腺素相关肽（PTHrP）及类视黄醇等，它们与核内转录因子相互作用，调节与控制软骨内成骨的进程。现对近年来软骨内成骨的主要调节因子研究综述如下。     

体外构建组织工程软骨种子细胞的研究进展

体外构建组织工程软骨的首要问题是种子细胞的来源,目前获得种子细胞的可能途径主要有以下几种:(1)培养扩增自体获得的软骨细胞;(2)同种异体软骨细胞;(3)骨髓基质干细胞及其他组织来源干细胞;(4)胚胎干细胞;(5)基因修饰细胞。本文就当前体外构建组织工程软骨的种子细胞研究进展综述如下:1自体软骨细胞自体软骨细胞可由关节软骨、骺板软骨、软骨膜、肋软骨和耳软骨等分离培养获得。软骨细胞是构成透明关节软骨的唯一细胞成分,是终末分化细胞,具有高度特异性。软骨细胞的主要功能是维持软骨基质成分的稳定。新分离的关节软骨细胞在最初的数天…     

骨组织工程学种子细胞研究进展

骨组织工程是目前组织工程学中最具有前途和临床应用可行性的研究领域之一,种子细胞是组织工程骨构建和应用研究中的首要环节和基本要素,成骨细胞是骨组织工程的种子细胞。近年来对于成骨细胞来源的选择、干细胞向成骨细胞诱导分化的调节以及成骨细胞的体外扩增都进行了深入的研究。本文结合国内外研究成果,对骨组织工程学种子细胞的研究现状进行回顾,并对其研究前景作一展望。     

壳聚糖在关节软骨组织工程中应用的研究进展

关节软骨一旦被损伤，因其缺乏自身血液循环系统，仅靠关节滑液提供大部分营养。随着年龄的增长，软骨细胞的合成能力下降，故关节软骨损伤后很难修复。虽然40多年来许多修复技术被广泛应用，但是至今还没有一种方法可以让受损软骨持续再生，从而达到完全修复的目的。组织工程的兴起在软骨的再生以及受损软骨的治疗方面显示出巨大的潜力。支架材料作为人工细胞外基质承载种子细胞是组织工程研究的重要内容之一。近年来，以壳聚糖为支架的材料及其在矫形组织工程中的应用正受到越来越多的关注。壳聚糖是一种理想的高分子生物材料，它具有机体反应小、天然抗菌性以及具有可任意塑性如多孔结构的特点，使其能够适合细胞的内在生长以及骨的传导，在组织工程中显示出巨大的应用价值。     

The role of cell seeding density and nutrient supply for articular cartilage tissue engineering with deformational loading

OBJECTIVE: Functional tissue engineering (FTE) of articular cartilage involves the use of physiologically relevant mechanical signals to encourage the growth of engineered constructs. The goal of this study was to determine the utility of deformational loading in enhancing the mechanical properties of chondrocyte-seeded agarose hydrogels, and to investigate the role of initial cell seeding density and nutrient supply in this process. DESIGN: Chondrocyte-seeded agarose hydrogels were cultured in free-swelling conditions or with intermittent deformational loading (10% deformation, 1 Hz, 1 h on/ 1 h off, 3 h per day, five days per week) over a two-month culture period. Disks were seeded at lower (10 million cells/ml) and higher (60 million cells/ml) seeding densities in the context of a greater medium supply than previous studies (decreasing the number of cells/ml feed medium/day) and with an increasing concentration of fetal bovine serum (10 or 20% FBS). RESULTS: Under these more optimal nutrient conditions, at higher seeding densities and high serum concentration (20% FBS), dynamically loaded constructs show >2-fold increases in material properties relative to free-swelling controls. After two months of culture, dynamically loaded constructs achieved a Young's modulus of approximately 185 kPa and a dynamic modulus (at 1 Hz) of approximately 1.6 MPa, with a frequency dependent response similar to that of the native tissue. These values represent approximately 3/4 and approximately 1/4 the values measured for the native tissue, respectively. While significant differences were found in mechanical properties, staining and bulk measurements of both proteoglycan and collagen content of higher seeding density constructs revealed no significant differences between free-swelling and loading groups. This finding indicates that deformational loading may act to increase material properties via differences in the structural organization, the production of small linker ECM molecules, or by modulating the size of macromolecular proteoglycan aggregates. CONCLUSIONS: Taken together, these results point to the utility of dynamic deformational loading in the mechanical preconditioning of engineered articular cartilage constructs and the necessity for increasing feed media volume and serum supplementation with increasing cell seeding densities.     

Experimental study on tissue engineering of the small intestine by mesenchymal stem cell seeding.

BACKGROUND: We have succeeded in regenerating the small intestine by the use of tissue engineering techniques. However, the regenerated intestine proved to lack the muscle layer, which is essential for functional peristalsis. To induce regeneration of the muscle layer, we focused on autologous mesenchymal stem cells (MSC) as a source of muscle tissue. The aim of this study was to investigate the effect of MSC seeding onto the collagen scaffold on induction of the muscle layer. MATERIALS AND METHODS: We used six female beagle dogs. The small intestine was resected over a length of 5 cm and reconstructed by a collagen sponge graft in the same way as in our previous study. Autologous MSC derived from bone marrow (10(7) cells) were seeded onto the collagen sponge just before implantation. Animals were sacrificed at 2, 4, and 16 weeks after surgery, and specimens were examined histologically. RESULTS: All six dogs survived until the scheduled time of sacrifice. At 4 weeks, regeneration of the intestine was observed at the reconstructed site. Cells positive for alpha-smooth muscle actin appeared on the scaffold in the MSC-seeded group. However, they disappeared by 16 weeks and only a thin muscle layer regenerated beneath the mucosal layer, although the regenerated mucosal layer covered the luminal surface of the regenerated intestine. CONCLUSIONS: MSC seeding induced a transient distribution of cells positive for alpha-smooth muscle actin on the scaffold, but did not induce regeneration of the muscle layer. Further investigation is necessary to achieve this aim.     

骨组织工程中种子细胞与材料黏附的有关蛋白及影响因素

骨组织工程近年的迅速发展为人们解决大段骨缺损的治疗难题提供了另一种途径。在骨组织工程研究中,细胞与支架材料的相互作用一直都是研究的重要领域,其核心是种子细胞在细胞外基质支架材料上的黏附。作为锚合依赖性细胞,成骨细胞在种植体表面的黏附、丛集是接触成骨的关键。只有当细胞与材料界面发生适当的黏附后,细胞才能进行迁移、增殖和分化。可以说,组织工程成功与否的关键之一就在于细胞在支架材料表面的黏附程度。     

Donor cell fate in tissue engineering for articular cartilage repair

Articular cartilage repair is a clinical challenge because of its limited intrinsic healing potential. Considerable research has focused on tissue engineering and transplantation of viable chondrogenic cells to enhance cartilage regeneration. However, the question remains: do transplanted allogenic cells survive in the repair with time? This study assessed donor cell fate after transplantation of male New Zealand White rabbit perichondrium cell and polylactic acid constructs into osteochondral defects created in the medial femoral condyles of female New Zealand White rabbits. Repair tissue was harvested at 0, 1, 2, 3, 7, and 28 days after implantation and was evaluated for cell viability and total cell number using confocal microscopic analysis. The number of donor cells in each sample was estimated using quantitative polymerase chain reaction targeting a gender-specific gene present on the Y-chromosome, the sex-determining region Y gene, and a control deoxyribonucleic acid present in male and female cell deoxyribonucleic acid, the matrix metalloproteinase-1 gene promoter. Average cell viability was found to be 87% or more at all times. Donor cells were present in repair tissue for 28 days after implantation. However, the number of donor cells declined from approximately 1 million at Time 0 to approximately 140,000 at 28 days. This decline in donor cells was accompanied by a significant influx of host cells into the repair tissue. This study shows that the sex-determining region Y gene is a valuable marker for tracking the fate of transplanted allogenic cells in tissue engineering.